Two-tone door chime



Nov. 8, 1966 K. E. ROSWELL. 3,284,797

TWO-TONE noon GHIME Filed- March 25, 1963 4 Sheets-Sheet l =:]UU 20 1 LQUUU 2 ZEUUUUU l8 A l -JUUUUU] i 5150mm 7; ,M

INVENTOR. KENNETH E. ROSWELL BY 7 4%, 971W /4 A A TTORNEYS 1956 K. E. ROSWELL 3,284,797

TWO-TONE DOOR CHINE Filed March 25. 1963 4 Sheets-Sheet 2 INVENTOR. KENNETH E. ROSWELL af 777m? 0 A TTORNEYS 1956 K. E. ROSWELL 3,284,797

TWO-TONE DOOR cams Filed March 25. 1963 4 Sheets-Sheet 3 625 486 52 50a 48a 62a VENTOR. KENNE E. ROSWELL awmww A7 TORNEYS Nov. 8, 1966 K. E. ROSWELL 43,284,797

TWO-TONE DOOR CHIME Filed March 25. 1963 4 Sheets-Sheet 4 9 IN VENTOR.

KENNETH E. ROSWELL United States Patent M 3,284,797 TWO-TONE DOOR CHIME Kenneth E. Roswell, Fairlield, Conu., assignor to Edwards Company Inc., a corporation of Connecticut Filed Mar. 25, 1963, Ser. No. 267,613 7 Claims. (Cl. 340392) The present invention relates to chimes and provides a two-tone door chime of the type which includes two spaced apart tone bars that are struck, by a solenoid operated striker, either individually, to sound a single note tone, or together in rapid sequence, to sound a two note tone.

In a door chime of this type, the character and quality of the sounded tones are quite important. However, in producing door chimes there are other factors that affect the desirability of door chimes, such as the size, weight, appearance, useful life, and cost of the door chimes. When these factors are used to determine the design of the chime, the tonal characteristics of the chime usually suffer.

The present invention contemplates a two-tone chime which has pleasing tonal characteristics and at the same time is compact, light weight, unobstrusive and inexpensive. Therefore, in accordance with the present invention, a two-tone door chime is provided which has twotone bars, a solenoid operated striker to strike the tone bars to make them vibrate, a housing holding the tone bars and the striker in a functioning relationship and mounting means for mounting the two-tone chime.

The tone bars are mounted parallel to each other on opposite sides of the housing and the striker is mounted within the housing between the tone bars. The housing is divided into two chambers. Both of these chambers have a port which is sized and positioned to make the two chambers separate resonating chambers mounted back to back. One tone bar is mounted in front of each port and the solenoid operated striker is fixed to a turret which is mounted in a passageway between the two resonating chambers. The striker strikes out in both directions through the chamber ports to hit the tone bars. When the tone bars are hit they vibrate. The resonating chambers reinforce the sound produced by these vibrations producing loud and clear tones.

To adjust the distance the striker must travel to hit the tone bars, the position of the turret on which the striker is mounted can be changed. It can be rotated to simultaneously increase or decrease the distance the striker must travel to both the tone bars, or it can also be positioned back and forth in the passageway to increase the distance the striker must travel to hit one of the tone bars while decreasing the distance it must travel to hit the other. However, no matter what its position or orienta tion, the configuration of the turret is such that it is always in close proximity to the walls of the passageway to limit the flow of air between the chambers.

With the above arrangement, the housing for the chimes functions as the resonating chambers, the support for the striker, and the support for the chime bars. This permits a simple, compact, one piece construction. Further, with this arrangement the striker may be easily adjusted for optimum striking of the tone bars.

Other features of the present two-tone chime are improvements in the solenoid actuated striker mechanism, chimes and mounting means. First, with respect to the solenoid striker, it contains a paramagnetic striker. This striker is held within the bores of two spool wound coils by bearings supporting the striker on either side of the coils. To hold the bearings and spools in place, a metal tube is provided. This tube is made of steel and has a slot which runs its entire length so that the interior dimen- 3,284,797 Patented Nov. 8, 1966 sions of the tube may be changed by varying the width of the slot. This tube is positioned around the bearings and spools and the slot adjusted so that the interior of the tube exerts force on the periphery of the spools and bearings to hold them in place. The force exerted by the tube keeps the bearing and the coil bores aligned, permitting the striker to move freely in the bearings and the coils. In addition, the slot simplifies making connections to the coils inside the tube and cuts eddy current lossesin the steel tube, which is used as a path for the magnetic field of the coils.

Another feature of this striker is fiat springs which are attached between each bearing and that portion of the shaft extending through that bearing to provide axial force to bias the plunger. These springs also exert a force transverse to the axis of the shaft. Both springs are arranged to exert this transverse force in the same direction, holding the shaft still against the same side of each bearingso the shaft does not vibrate back and forth in the bearings and make a buzzing sound when the coils are energized. The buzzing is especially objectionable in this particular chime design because the solenoid plunger is positioned in the resonating chambers and therefore any noise made by the plunger is magnified by the chambers.

As for the tone bars, they are made out of aluminum, a metal which has many characteristics that are desirable in tone bars. However, up to now aluminum tone bars have not been successfully used because known methods of mounting tone bars involve the use of elastic grommets which so dampen the vibration of aluminum tone bars that they do not give loud clear signals.

To obtain sufiicient sound from the aluminum bars, the applicant mounts his tone bars on supports with metal wire which .is rigidly attached to the supports and to the tone bars at the vibrational nodal points of the bars. It has been found that rigidly attaching the wire to the supports and to the tone bars in this manner effectively eliminates movement of the portion of the wire mount in contact with the supports and bar with respect to the supports and bars but does not have a deleterious effect on the vibration of the tone bar.

Still another important feature of the two-tone chime is the structure provided for mounting the two-tone chime. In this structure the mechanical and electrical connec tions for the chime are made by sliding contact between the chimes and a bracket that is mounted on the wall. To this end three parallel metallic strips are positioned on the back of the housing and held there under compression so that they bow out. In the back of the housing on both sides of the bowed strips are two slots which narrow towards one end. The bracket has bent ears at either end which mate with the slots to fix the bracket to the walls and a number of raised fasteners which make contact with the bowed strips when the ears of the bracket are positioned in the slots. The strips are wired to the striker so that all that is necessary to make the electrical connections to the striker is to make the electrical connections to the fasteners and mount the chime on the bracket.

These and. other features of the two-tone chime are best understood by reference to the accompanying drawings of embodiments of the same in which:

FIG. 1 is a front View of the two-tone chime with the front of the case broken away to show the working elements of the chime.

FIG. 2 is a back view of the two-tone chime.

FIG. 3 is a side view of the two-tone chime with the tone bar broken away to show the resonating chamber port and slots for holding the supports for the tone bar.

FIG. 4 is a section taken along the line 4-4 in FIG. 3 and shows the inner workings of the solenoid opera-ted striker.

FIG. 5 is a view of a bias spring for the striker that has been straightened out.

FIG. 6 is a portion of the tone bar showing the mount for attaching it to the chime box.

FIG. 7 is a wiring schematic showing how the coils of the solenoids are attached. to a circuit.

FIG. 8 is a front view of the mounting bracket for the two-tone chimes.

FIG. 9 is a side View of the mounting bracket for twotone chime shown mounted on a wall and with the twotone chime.

FIG. 10 shows portions of a tone bar provided with a hole for changing the tonal characteristics of the bar.

In the illustrated embodiment, the housing 10 for the two-tone chime is a substantially rectangular plastic case which has been molded in separate front 12 and back 14 sections that fit together. Lips l6 and 18 on the front 12 and back 14 sections of the housing respectively, mate when the sections are put together to form a substantially airtight joint between the sections.

The housing is divided with two chambers 20 and. 22. Both the chambers 20 and 22 have openings 26 and 28 that are on opposite sides of the housing in recesses 30 and 32 respectively. The tone bars 34 and 36 for the chime are positioned in these recesses with the smaller tone bar 34 in front of the opening for the small chamber 20 and the larger tone bar 36 in front of the opening of the large chamber 22. Each of the chambers is tuned to respond to the frequency of vibration of the tone bar mounted in front of it so that vibrations of the tone bar will set up sympathetic vibrations of the air in the chamher.

The openings for the chambers are made oblong and fairly large. The openings are oblong so that the moving air mass in the cavities is directed at the bars and does not escape around the bars and they are large to make the cavities broadly tuned so that positioning of the tone bars relative to the cavity is not too critical.

The solenoid actuated striking mechanism is fixed in a turret 38 mounted in a passageway 40 between the chambers, and as can best be seen in FIG. 4, includes a paramagnetic plunger 42 centrally mounted on nonmagnetic shaft 44 having two plastic covered tips 46a and 46b to form a paramagnetic striker. The paramagnetic plunger is forced on two knurled sections 48a and 48b of the shaft because if it were fitted to the shaft, in assembling, the shaft would become grooved and thereby effect the movement of the shaft through plastic bearings in which it is supported. Alternatively, the shaft can be made of two pieces fitted in the ends of the paramagnetic plunger to eliminate possibility of the shaft becoming grooved.

The plunger moves freely in the bore of nonmetallic spools 50a and 50b. These spools are separated by a paramagnetic washer 52 and have paramagnetic washers 54a and 54b at each end. Coated wire is wound around each of the spools 50a and 50b to form two separate magnetic coils 56a and 56b which are adapted to be connected (as shown in FIG. 7), in series with the front 58a and back 58b door buttons and a low voltage source 60. When either door button is pressed, it energizes its respective coil which in turn sets up a magnetic field. The magnetic field acts on the paramagnetic plunger 42 to cause it to move in the bore of the spools.

The plunger and the shaft are kept properly aligned within the spools by the bearings 62a and 62b through which the shaft moves, and the spools 50, washers 52 and 54 and bearings 62 are all held in place by a tube 64 made of steel, which is split along its whole length. In assembling, the split is spread to increase the diameter of the tube. The spools 50, the washers 52 and 54, the shaft 44, the plunger 42 and the bearings 62 are then inserted into the tube 64. When all of the parts are properly positioned in the tube the pressure on the split is released so the tube bears against the washers, the spools, and the bearings. In most situations this will provide all the restraint necessary to hold the plunger parts properly positioned alternatively, the diameter of the tube can be a little larger to provide easier insertion of the parts in the tube and the tube can be clamped to the parts by force exerted on the tube by an exterior member such as turret 38.

In addition to keeping the parts of the device properly aligned, the steel tube also provides a return magnetic path for the flux produced by the coils. The split in the tube substantially limits the eddy current losses in the tube and at the same time provides a convenient place through which the electrical leads to the coils may be brought.

The solenoid plunger is provided with two flat springs. These fiat springs consist of metal strips 68a and 68b each attached at one end to the outside of one of the bearings 62 and at the other end to the shaft 44 in proximity to one of the plastic tips 46. Each of the strips is provided with an oblong opening 70 which fits over a protuberance 72 on the bearing 62. Each of the strips also has a circular opening 74 through which the shaft may pass freely and a keyhole-shaped opening '76 into which the end of the shaft is forced. When the strip is properly positioned on the bearing and shaft, the plastic protuberance 72 is distorted by heat to attach the strip to the bearing.

With the coils unenergized, the springs exert a differential force on the striker to position the plunger between the two coils at a position where the forces exerted by the springs on the shaft are in equilibrium.

To move the plunger from the spring equilibrium position, one of the door buttons 58 is pressed. When the front door button 58a is pressed it completes the circuit between the low voltage source and the short coil 56a setting up a magnetic field around the coil. The field passes along the paramagnetic tube 64, through the paramagnetic washer 54a and the bore of the shorter spool 50a into the plunger 42. From there the field passes across the air gap between the plunger 42 and the central washer 52 to complete the path. The field in the bore of the shorter spool exerts a force on the plunger 42 which causes it to move from the spring force equilibrium position to a new position in the shorter spool 50a. In moving, the plunger 42 first overshoots its new position causing the plastic tip 46a to strike the shorter tone bar 34. When the plunger settles in the new position the tip 46a is back away from the struck tone bar and does not interfere with the vibrations.

When the front door button 53a is released it opens the circuit through coil 56a. This dissipates the magnetic field ending the force it exerted on the plunger. In the absence of the force from the magnetic field, springs 68a and 6812 return the plunger to the spring equilibrium position and in doing so cause the plunger to overtravel the spring equilibrium position so that the plastic tip 46b strikes the longer tone bar 36 before the plunger settles in the spring equilibrium position. As a result two distinct chime tones are sounded for the front door.

When the back door button 58b is pressed it completes the circuit through the larger coil 56]) setting up a magnetic field that passes along the paramagnetic tube 64, through the bore of the longer spool 54b into the plunger 42. From there the field passes across the air gap between the plunger and central washer 52 and through the central washer 52 to complete the path. This field exerts a force on the paramagnetic plunger to move it from the spring force equilibrium position to a new position in the larger spool 54b and causes tip 46b to strike the longer tone bar 36 when the plunger overshoots its new position while moving into it. When pressure on back door button is released and the magnetic field dissipated the plunger returns to the spring force equilibrium position without tip 48a hitting the shorter tone bar. Therefore, when the back door button is touched it hits only one tone bar to give a single note signal.

In addition to providing the differential force for the' plunger, the springs also exert a force transverse to the axis of the shaft. Both the springs are adjusted so this force is exerted in the same direction. With the transverse force of both springs being exerted in the same direction, the shaft is held against the same side of both bearings to eliminate objectionable hum while either one of the coils is energized. The clearances between the bearings and the shaft are made smaller than the clearance between the plunger and the interior walls of the spool bores so that the plunger will not rub the interior of the spools and thereby decrease the efiiciency of the solenoid actuated striker.

To assure the transverse force exerted by both springs is in the same direction, a bead 78 which slides into the slot in the tube 64 is provided on each of the bearings 62. This fixes the position of the protuberances 72 with respect to the slot, and since the position of the bead relative to the protuberance 72 is the same for both bearings, the springs fixed to the bearings by melting the protuberance 72 will both be oriented in the same direction. With the springs oriented in the same direction the force they exert on the bearings is in the same direction.

The adjustment of the striker is critical. If the striker in the spring force equilibrium position is too far away from a tone bar it will not strike a sharp enough blow. If the strike-r is too close to the tone bar it will interfere with the vibrations of the tone bar. Adjustment of the striker is further complicated by the fact that the tone bars of the two-tone chimes are struck by opposite ends of the same striker so that adjusting the striker for an optimum position with respect to one of the tone bars afiects its adjustment with respect to the other tone bar.

The adjustments of the plunger in the present invention is brought about by movement of the turret 38 which mounts the plunger. The turret is attached to the housing by a screw 80 that passes through a slot 82 in the housing and grasps the turret 38 with its threads. With the screw loosened the turret may be positioned back and forth or rotated in the slot. Movement of the turret back and forth in the slot increases the distance the striker has to travel to hit one of the bars while decreasing the distance it has to travel to hit the other. Rotating the turret simultaneously increases or simultaneously decreases the distance which the striker must travel to hit both tone bars. Whether the distance the striker must travel to hit the tone bars is increasing or decreasing depends on whether the shaft 44 moved toward or away from alignment with a perpendicular to bot-h the tone bars. Therefore, it is possible to quickly adjust the striker for optimum striking distance by first correctly positioning the turret in the slot and then rotating the turret until optimum results are obtained for both tone bars.

To limit the flow of air between the chambers a passageway is formed by means of two wall sections 83 and 84 and the turret 38 is provided with arcuate edges 79 and 81. No matter what the position or orientation of the turret in the slot the arcuate edges are in close proximity to the wall sections 83 and 84 to limit the flow of air through the opening. To prevent the turret moving once it has been adjusted a portion 86 of the housing against which the turret rests is stippled to provide a friction surface.

To provide a pleasing tonal arrangement between the two notes struck for the front door it is desirable to have the frequency of the vibration of the tone bars determined within close tolerances. To control the frequency of vibration both the thickness and length of the tone bar must be controlled. It has been found that aluminum can be rolled within close tolerances and there-fore would be desirable for use on the tone bars. In addition, the overtones of vibrating aluminum bars are pleasing, and alumimum is easy to work with. However, up to now it has not been possible to use aluminum for tone bars because the means of mounting tone bars has been inefficient, making it impossible to obtain a sufficient sound from aluminum.

In the present invention this problem is overcome by fixing the wire mounts to the aluminum bar and to the support members for the mounts to minimize movement of those portions of the wire in cont-act with the tone bars and the support members with respect to the tone bar and support members. This is most efficiently done by first putting a slot in the edge of the tone bar which is slight ly wider and deeper than the diameter of the wire 88, inserting the wire into the slot and deforming the metal of the tone bar around the slot, forcing it against the wire to stake the wire to the tone bar. Another way this could be done is by forcing the steel wire 88 into the sides of the aluminum tone bar by a ram which is broader than the .thickness of the wire so that as the wire is forced into the bar there is a point at which the ram contacts the tone bar on both sides of the wire forcing the metal of the tone bar into the void left behind the wire. Wire 88 is fixed to the bar in either of these manners at the two vibrational nodal points 90 and 92 of the bar positioned one-half a wavelength of the bar apart. At each of the nodal points 90 and 92, wire is so attached to the bar in two places 94 and 96.

With such fixed connections between the wire and the aluminum there can not be any movement between the bar and the portion of the wire attached ltO the bar. This tends to damp .out parasitica-l vibrations of the wire mount which would otherwise add harshness to the struck tones.

The described method is the preferred method of fixing the wire to the tone bar because it permits accurate positioning of the wires with respect to the vibrational nodal points of the bar. However, other methods of fixing the tone wire to the tone bar may be employed. For example, holes smaller than the diameter of the wire may be drilled in the .tone bar at the bars vibrational nodal points and the wire forced into the holes to fix it to the tone bar. Also holes larger in diameter than the wire may be employed and the wire fixed to the tone bar by epoxy resin or other similar bonding material.

At each of the two places 90 and 92 the wire is inserted into a slot in a soft metal foot which is then deformed at 102 to fix the foot to the wire. into slots 104 and 106 on either side of the chamber openin-g prior to assembling the two sections and held in place by friction between the foot and the wall of the slot. Between the foot 100 and the bar 34 each wire is bent substantially as shown at 108 in FIG. 6, to form a spring. This permits the portion of the bar at the nodal point to move relative to the foot so that the efficiency of the mount is further increased.

Variations in the tonal characteristics of the bar may be obtained by use of a muter 98 positioned around the bar. Also, as shown in FIG. 10, holes 99 may be drilled in the bars preferably in the proximity of the bars vibrational nodal points. Variations in the size, shape and position of such ho les change the tonal characteristics markedly.

To conduct electricity to the solenoid operated striker mechanism and to connect the chime assembly to the wall, a separate mounting bracket 110 is provided. This bracket has terminal strip 112 with three terminals each provided with a screw threaded to the terminal. The bracket is also provided with two slots 114 and 116 for connecting the bracket to walls.

After the bracket is mounted on the wall 118 the connection to the door buttons 58 and the low voltage excitation are made to the terminals. A common wire ,12() from the source 60 is connected to the middle terminal 122 and the connections 124 and 126 from the'door button? 58a and 58b going to terminals 128 and 130 respective y.

These feet are inserted The back portion 14 of the housing is provided with a recess 132. Coming out through the recess are three metallic strips 134, 136 and 138. These strips are woven through a number of openings in the casing and are held there in compression between stops so that the strips are bowed out of the plane of the back surface of the housing. Each strip has an arcuate tip 140 at one end and a neck 142 at the other. The tip end of each strip is inserted through a slot in a rib 144 provided inside the back of the housing and two slots in the recessed portion 132 on the back of the housing. The tip then comes in contact with a stop 146. The tip is forced against this stop 146 bowing the strip out from the surface of the back section until a raised protrusion 148 on the strip passes through the slot in the plastic rib 144 on the inside of the case. Pressure on the strip is then released allowing the protrusion 148 to come to rest against the plastic rib 144 to hold the strip in compression between the stop 146 and the rib 144 so that the strip remains bowed out of the plane of the back section. The wires from the coils 56 are then attached to the neck portions 142 of the strips, one wire from each coil being attached to the central strip 136 and the other wire from each coil being attached'separately to the other strips 134 and 138.

Both ends of the bracket are bent to form upstanding ears substantially in the form shown at 150 that stand out from the surface of the wall. When the housing is properly positioned on the bracket these cars enter slots substantially of the form shown at 152 on either side of the housing. The'ears easily fit into the Wide end of the slots and when the casing is moved relative to the bracket they slide into the narrow end where they grasp the casing as shown in FIG. 9. With the ears forced to the narrow end of the slots, the bowed strips are held compressed against the heads of the screws of the terminals by the spring action provided by the bowing, completing the electrical connections to the chime.

Adjacent both ears of the bracket there is a protrusion 154 and adjacent the slots on the housing there is an identation 156. When the housing is properly fixed to the bracket the protrusions 154 are in these indentations 156. This provides a detent action which positively fixes the ears in the slots. To prevent reversal of the bell circuits, the ends 158 and 160 of each ear are bent in opposite directions 50 that the ears will fit into the slots in only one direction. The chime assembly may be arranged either horizontally or vertically on the wall. If the chime assembly is to be arranged horizontally the bracket is fixed to the wall vertically and the chime assembly positioned horizontally thereon. If the chime assembly is to be arranged vertically the bracket is fixed horizontally on the wall and the chime assembly positioned thereon with the narrow end of slots 152 pointing up.

From the above description it should be apparent that a number of features of the invention have application outside the particular two-tone chime described. Therefore, it should be understood that with respect to those features the invention is not limited to the two-tone chime.

It will be further understood this is intended to cover all changes and modifications of the described form of the structure herein chosen for the purpose of. illustration which do not constitute departures from the'spirit and scope of the invention.

It is claimed:

1. A two-tone chime assembly comprising:

(a) a pair of spaced tone elements which vibrate when struck;

(b) a pair of resonating chambers positioned back to back, the first of said chambers having an opening positioned with respect to the first of the spaced tone elements to reinforce the sound produced by the vibrations of the first tone element and the sec- 0nd of said resonating chambers having an opening positioned with respect to the second of said spaced tone elements to reinforce the sound produced by the vibrations of the second tone element, said two chambers each having a second opening which is common to both chambers; and

(c) at least one solenoid actuated striking means positioned in said second opening in said two chambers, said striking means having portions .which are closely juxtapositioned with respect to the sidewalls of the second opening of the two chambers to substantially isolate the air in each of the chambers from the air in the other.

2. A two-tone chime assembly comprising:

(a) a pair of spaced tone elements which vibrate when struck;

(b) a pair of resonating chambers positioned back to back between the spaced tone bars, the first of said chambers having an opening which is positioned to reinforce the sound produced by the first of the tone elements, the second of said chambers having an opening which .is positioned to reinforce the sound produced by the second of said tone elemerits, said resonating chambers having a separating barrier therebetween with an opening which joins the two resonating chambers; and

(c) a solenoid operated striking means positioned in said opening in said barrier, said solenoid actuating striking means having portions sized and shaped to close said opening in said barrier sufficiently to substantially isolate the air in each chamber from the other chamber and said solenoid actuated striking means having a first striker element adapted to operate in the first of said resonating chambers to strike the first of said tone elements anda second striker element adapted to operate in the second of said resonating chambers to strike the second of said tone elements.

3. The two-tone chime assembly of claim 2 wherein said solenoid actuated striking means has two curved surfaces in opposite sides thereof which remain in close juxtaposition with the sidewalls of the opening in said barrier for a number of different orientations of said solenoid actuated striker means.

4. The two-tone chime assembly of claim 2 wherein the sidewalls of the opening in said barrier are sufficiently long to remain in close juxtaposition with the solenoid actuated striking means for a number of angular positions which the solenoid actuated striking means assumes when rotated relative to the said sidewalls of the barrier.

5. A two-tone chime assembly comprising:

(a) an enclosure with a separate opening in each of two opposite sides thereof and with a wall which separates said enclosure into two resonating chambers each with one of said openings therein, said wall having an opening therein which joins two chambers together;

(b) a pair of spaced tone elements which vibrate when struck, the first of said tone elements being positioned adjacent one of said holes in the sides of the enclosure so that its vibrations will be strengthened and the second of said tone elements being positioned adjacent the other of said holes in the side of the enclosure so that its vibrations will be strengthened; and

(c) a solenoid operated striking means positioned in said-opening in said wall, said solenoid actuated striking means having sides which are closely juxtapositioned with respect to the sidewalls of the opening in the barrier so as to substantially isolate the air in each chamber from the other chamber and said solenoid actuated striking means having a striker tip for each of said tone elements which can be actuated to separately strike said tone elements.

6. The two-tone chime of claim wherein a said solenoid actuated striking means has opposite curved sides which remain closely juxtapositioned with respect to the sidewalls of the hole in the wall for a number of different angular orientations of the solenoid actuated striking means so that the distance between said tips and said tone elements can be adjusted while maintaining the isolation between the air of the chambers by rotating the solenoid actuated striker means and wherein the sidewalls of the opening in the wall are sufficiently long to remain in close juxtaposition with respect to the sides of the solenoid actuated striking means for a number of different positions of the solenoid actuated striking means so that the distance between said tips and said tone elements can be adjusted while maintaining the isolation between the air of the chambers by positioning the solenoid actuated striking means back and forth along the axis of the opening in the wall.

7. A two-tone chime assembly comprising:

(a) a pair of spaced tone elements which vibrate when struck;

(b) a pair of resonating chambers;

(c) the first of said chambers having an opening positioned with respect to the first of the spaced tone elements to reinforce the sound produced by the vibrations of the first tone element and the second of said resonating chambers having an opening positioned with respect to the second of said spaced tone elements to reinforce the sound produced by the vibrations of the second tone element, said two chambers each having at least one second opening connecting the two chambers; and

(d) at least one solenoid actuated striking means positioned in said second opening in said two chambers, said striking means having portions which are closely juxtapositioned with respect to the sidewalls of the second opening in said two chambers to substantially isolate the air in one chamber from the air in the other chamber.

References Cited by the Examiner UNITED STATES PATENTS 1,446,095 2/1923 Karaus 29-1695 1,817,592 8/1931 Sokolotf 317- 1,920,219 8/1933 Siebs 174-52 1,931,701 10/1933 Pascoe 317-190 1,936,802 11/1933 Rugg 174-52 2,265,816 12/ 1941 Rittenhouse 340-92 2,290,717 7/1942 Swanson 340-392 X 2,333,875 11/1943 McMullen 84-405 2,386,738 10/ 1945 Corbett 340392 2,470,827 5/ 1949 Miller 340-392 2,484,745 10/1949 Rowe 84-405 2,487,767 11/1949 Slaker 340-392 2,649,652 8/ 3 Duncan 29-1695 2,659,074 11/ 1953 Alexander 84-405 2,810,123 10/1957 McEvoy 84-405 2,844,767 7/ 1958 Houdek 340-401 2,966,089 12/ 1960 'Gercken 84-405 NEIL C. READ, Primaly Examiner.

W. C. GLEICHMAN, I. I LEVIN,

Assistant Examiners. 

1. A TWO-TONE CHIME ASSEMBLY COMPRISING: (A) A PAIR OF SPACED TONE ELEMENTS WHICH VIBRATE WHEN STRUCK; (B) A PAIR OF RESONATING CHAMBERS POSITIONED BACK TO BACK, THE FIRST OF SAID CHAMBERS HAVING AN OPENING POSITIONED WITH RESPECT TO THE FIRST OF THE SPACED TONE ELEMENTS TO REINFORCE THE SOUND PRODUCED BY THE VIBRATIONS OF THE FIRST TONE ELEMENT AND THE SECONE OF SAID RESONATING CHAMBERS HAVING AN OPENING POSITIONED WITH RESPECT TO THE SECOND OF SAID SPACED TONE ELEMENTS TO REINFORCE THE SOUND PRODUCED BY THE VIBRATIONS OF THE SECOND TONE ELEMENT, SAID TWO CHAMBERS EACH HAVING A SECOND OPENING WHICH IS COMMON TO BOTH CHAMBERS; AND (E) AT LEAST ONE SOLENOID ACTUATED STRIKING MEANS POSITIONED IN SAID SECOND OPENING IN SAID TWO CHAMBERS, SAID STRIKING MEANS HAVING PORTIONS WHICH ARE CLOSELY JUXTAPOSED WITH RESPECT TO THE SIDEWALLS 